Regular Expression @RegexTip
Learn to use regular expressions by following RegexTip. From @JohnDCook. JohnDCook.com Joined November 2009-
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Emacs regex escape |, (, and ). For example, (a|b) in Perl becomes \(a\|b\) in Emacs.
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Flatten JSON files so they're easier to grep: github.com/TomNomNom/gron
Graphemes johndcook.com/blog/2015/03/0…
To group without capturing, use (?: ... ).
“Regular expressions aren’t random jumbles of punctuation—they’re carefully thought-out jumbles of punctuation!” -- The Perl Cookbook
\> represents an ending word boundary and match a position between two tokens. Some engines don't support this.
\< represents a beginning word boundary and match a position between two tokens. Some engines don't support this.
Awk regular expressions johndcook.com/blog/awk-regul…
\b matches a word boundary; \B matches anything but a word boundary.
Don't confuse \1 with $1. \1 is used inside a regex; $1 (in Perl) is used outside the regex after a match.
Many languages support Perl 5 regular expressions. For example, Microsoft .NET supports Perl 5 regex with some of its own extensions.
\d represents the numerical characters, or [0123456789]. Its complement is \D.
Using regular expressions in PowerShell johndcook.com/blog/powershel…
If you're going to work with regular expressions, it's worthwhile to learn Perl notation even if you don't intend to ever use Perl.
You can include comments inside a regex with (?# ... ). For example, /the\s+(?# One or more spaces)end
[a-z] matches all lower case letters. [-az] matches '-', 'a', or 'z'.
Perl stores the content of the previous match in $&, the text to the left of the match in $`, and the text to the right in $'.
Grep rewritten in Perl (and so it supports Perl regular expressions) johndcook.com/blog/2021/03/0…
Regular expressions in Rust docs.rs/regex/latest/r…
The greatest regex trick ever rexegg.com/regex-best-tri…
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